Evaporation from Bare Black Soil (Vertisol) under High Diurnally Fluctuating Evaporative Demand

The influence of various processes involved in the loss of water from bare soil under field condition, was examined with the help of lysimetric technique which, in turn, was estimated from the average volumetric water content and soil-water diffusivity values in black soils (Vertisols). Evaporation rate after 24 h (7.4 mm/day) decreased markedly to 1.2 mm/day in 20 day period. Evaporation during day time contributed to about 85% of the total (E actual) up to about 12 days. There was good agreement between predicted evaporation rate using Gardner and Hillel equation and the actual one after about 5 to 6 days with commencement of evaporation stage-III. The linear relationship between cumulative evaporation and square root of time was found to hold good up to a period of 12 days.